SANTA CLARA — Safety Antoine Bethea joined the 49ers’ growing list of wounded starters when a second-quarter concussion spelled his exit from Sunday’s 34-0 exhibition loss to the Denver Broncos.

Bethea was injured on an apparent blow to the face by wide receiver Cody Latimer on a downfield block. Other players immediately summoned 49ers trainers to tend to Bethea, who walked off the Levi’s Stadium field and later retreated to the locker room.

Bethea posted on Twitter: “I’m doing well and I appreciate all of the concern.”

“I think he’s OK. He’ll be in our prayers,” said rookie Jimmie Ward, who eventually moved to safety from his nickel back role.

Bethea started every game the past six seasons for the Indianapolis Colts. He was among six regular starters who suited up on defense, the others being outside linebackers Aldon Smith and Ahmad Brooks, cornerback Chris Culliver, safety Eric Reid and linebacker Michael Wilhoite.

Running back Frank Gore broke a 9-yard run on his first carry, during which dirt or sand could be seen kicked up by his linemen on the new turf. Gore said the surface felt “fast” and “great,” then jokingly added: “But you know, I’ve got great feet.” Gore’s 3-yard run on the next snap, on third-and-1, marked the end of his cameo.

Asked if he might be saved until the regular season, Gore replied: “I hope not. I love to be out there. I’m happy to be out there. I should’ve scored a touchdown (on the first run).”

Teammates weren’t concerned about Phil Dawson missing his two field-goal attempts wide right, from 55 and 44 yards. “Let him get his footing, get a feel for the wind in the stadium,” fullback Bruce Miller said. “He’ll get it together. He’ll get it down.” Dawson made 32 of 36 field goals last season.

Levi’s Stadium’s first play surprisingly went to Miller, who returned the opening kickoff 29 yards to the 35. “It just looked like a blur. That wasn’t supposed to happen,” Miller said.